1. Field of the Invention
The present invention relates to a method of assembling a tire and a wheel, a recording medium which records a phase angle operating program at the time of assembling a tire and a wheel, and an assembled tire and wheel unit. More particularly, the present invention relates to method of assembling a tire and a wheel, a recording medium which records a phase angle operating program at the time of assembling a tire and a wheel for obtaining an optimum phase angle at the time of assembling the tire and the wheel as a predicted angle, and an assembled tire and wheel unit which is assembled in accordance with the method of assembling a tire and a wheel.
2. Description of the Related Art
Conventionally, in order to prevent vibrations of a vehicle caused by unevenness on the peripheries of a tire and a wheel due to the irregularities at the time of manufacturing the single wheel unit and the single tire unit, a positional relationship between the wheel and the tire during assemble is intentionally selected and the assembling is effected in the positional relationship. The typical method is called radial force variation (RFV) primary matching. In this assembling method, a bottom position of a Fourier primary component of radial direction vibrations (radial run-out, the mean of the front side/reverse side of the wheel) of a single wheel unit and a peak position of an RFV primary component of a single tire are matched. This is because the RFV primary component of the single tire unit after the assembling is expected to be reduced by the value of the RFV primary component caused by the vibrations of the single wheel unit.
In addition to RFV caused by the above-described small vibrations on the periphery of the tire or unevenness of rigidity, unevenness on the periphery of the tire is also caused by unevenness of mass distribution which is called unbalance. This unbalance generates centrifugal force when the assembled tire and wheel unit is rotated and causes vibrations in a vehicle by exciting an axle at the primary frequency of rotation. After the wheel and the tire are assembled, this unbalance can be theoretically cancelled by adding balance weights having accurate masses one by one to each of specific places of flange portions at the front and reverse sides of the wheel, and balancing is actually routinely effected by a method (two-surface balancing method) in accordance with this principle using a commercially-available wheel balancer.
In an operation for correcting the unevenness of the assembled wheel and tire unit to prevent the vibrations of a vehicle, basically, the two aforementioned procedures are effected in succession and the adjustment is completed when these procedures are completed. Namely, the wheel and the tire which have been adjusted are lightened by an amount corresponding to the run-out of the wheel due to the RFV primary matching of the single tire.
However, deviation (unbalance) in the entire mass distribution which is determined after the assembling may be generated on the assembled unit by the RFV primary matching, therefore a balance weight which matches the entire amount of the deviation to be rectified is forcibly added to the assembled body from an exterior.
In this way, in accordance with the RFV primary matching, the RFV of the tire is reduced using the radial direction vibrations of the wheel which is one type of unevenness of the wheel, and the wheel and the tire are thereby assembled. The unbalance accompanying the assembling method is corrected by adding the balance weight, and the assembled tire and wheel unit is obtained.
However, the amount of balance weight required for correcting the unbalance is determined by the amounts of unbalance of the wheel and the tire and the positional relationship therebetween. As a result, in the uniform assembling of the wheel and the tire called the RVF primary matching, the effect of reducing RFV is small and the amount of balance weight is excessively large. In extreme cases, when the position of a wheel, whose vibrations are very small but which has a reasonable amount of unbalance, coincidentally matches perfectly the unbalance position of the tire at the time of effecting the assembling by the RFV primary matching, the absurd outcome is that the assembling method, in which the effect of reducing RFV is almost zero and the unbalance is the worst, ends up being intentionally selected.
Further, the excessively large balance weight is not preferable because of its appearance and is counter-productive to reducing the weight of the tire. Moreover, lead has been mainly used for the balance weight, however, since the use of lead is banned for social reasons such as environmental problems or the like, iron is considered as the alternative balance weight. Nevertheless, since the specific gravity of iron is smaller than that of lead, the volume per weight thereof increases. Thus, it is desirable that the amount of unbalance itself is reduced.
With the aforementioned in view, an object of the present invention is to obtain a method of assembling a tire and a wheel which can reduce the amount of unbalance, a recording medium which records a phase angle operating program at the time of assembling the tire and the wheel, and an assembled tire and wheel unit.
In order to achieve the above-described object, a first aspect of the present invention is a method of assembling a tire and a wheel, comprising the steps of: on the basis of a physical amount of unbalance which includes the magnitude and the position of the amount of unbalance of a tire and the magnitude and the position of the amount of unbalance of a wheel for assembling with the tire, obtaining a predicted angle for assembling the tire and the wheel using a predetermined evaluation function for evaluating the relationship between the tire and the wheel at the time of assembly; and assembling the tire and the wheel at the predicted angle.
A second aspect of the present invention is a method of assembling a tire and a wheel, comprising the steps of: on the basis of a physical amount of unbalance which includes the magnitude of the amount of unbalance on the axial direction end surfaces of a tire, the position of the amount of unbalance on the periphery of the end surface of the tire, the magnitude of the amount of unbalance on the axial direction end surfaces of a wheel for assembling with the tire, and the position of the amount of unbalance on the periphery of the end surface of the wheel, obtaining a predicted angle for assembling the tire and the wheel using a predetermined evaluation function which includes the phase angle at the time of assembling the tire and the wheel for evaluating the relationship between the tire and the wheel at the time of assembly; and assembling the tire and the wheel at the predicted angle.
A third aspect of the present invention is a method of assembling a tire and a wheel according to the first aspect or the second aspect of the present invention, wherein the evaluation function indicates the magnitude of the amount of static unbalance correction after the tire and the wheel are assembled.
A fourth aspect of the present invention is a method of assembling a tire and a wheel according to the second aspect of the present invention, wherein the evaluation function indicates the magnitude of at least one of the amounts of unbalance correction on the axial direction end surfaces of the wheel after the tire and the wheel are assembled.
A fifth aspect of the present invention is a method of assembling a tire and a wheel according to the second aspect of the present invention, wherein the physical amount of unbalance further includes a physical amount relating to radial direction vibrations of the tire and a physical amount relating to radial direction vibrations of the wheel, and the evaluation function indicates the physical amounts relating to the radial direction vibrations of the tire and the wheel after the tire and the wheel are assembled.
A sixth aspect of the present invention is a method of assembling a tire and a wheel according to the second aspect of the present invention, wherein the physical amount of unbalance further includes a physical amount relating to radial direction vibrations of the tire and a physical amount relating to radial direction vibrations of the wheel, and the evaluation function indicates the sum of the physical amount of the magnitude of at least one of the amounts of unbalance correction on the axial direction end surfaces of the wheel after the wheel and the tire are assembled and a weight is attached thereto, and the physical amount relating to the radial direction vibrations of the wheel and the tire after the tire and the wheel are assembled and a weight is attached thereto.
A seventh aspect of the present invention is a method of assembling a tire and a wheel according to the second aspect of the present invention, wherein the physical amount of unbalance further includes a physical amount relating to radial direction vibrations of the tire and a physical amount relating to radial direction vibrations of the wheel, and the evaluation function indicates, in a predetermined relationship, the physical amount of the magnitude of at least one of the amounts of unbalance correction on the axial direction end surfaces of the wheel after the wheel and the tire are assembled and a weight is attached thereto, and the physical amount relating to the radial direction vibrations of the wheel and the tire after the wheel and the tire are assembled and a weight is attached thereto.
An eighth aspect of the present invention is a method of assembling a tire and a wheel according to any one of the first through seventh aspects of the present invention, wherein a valve for intaking air is attached to the wheel.
A ninth aspect of the present invention is a method of assembling a tire and a wheel according to any one of the first through eighth aspects of the present invention, wherein the physical amount relating to radial direction vibrations of the wheel is radial run-out, and the physical amount relating to radial direction vibrations of the tire is at least one uniformity of radial force variation and lateral force variation.
A tenth aspect of the present invention is a record medium which records a phase angle operating program at the time of assembling a tire and a wheel in which an optimum phase angle at the time of assembling the tire and the wheel is obtained by a computer as a predicted angle, wherein: a physical amount of unbalance which includes the magnitude of the amount of unbalance on the axial direction end surfaces of a tire, the position of the amount of unbalance on the periphery of the end surface of the tire, the magnitude of the amount of unbalance on the axial direction end surfaces of a wheel for assembling with the tire, and the position of the amount of unbalance on the periphery of the end surface of the wheel is measured; and a predicted angle for assembling the tire and the wheel is obtained on the basis of the physical amount of unbalance using a predetermined evaluation function which includes a phase angle at the time of assembling the tire and the wheel for evaluating a relationship between the tire and the wheel at the time of assembly.
An eleventh aspect of the present invention is an assembling body of a tire and a wheel, wherein: a physical amount of unbalance which includes the magnitude of the amount of unbalance on the axial direction end surfaces of a tire, the position of the amount of unbalance on the periphery of the end surface of the tire, the magnitude of the amount of unbalance on the axial direction end surfaces of a wheel for assembling with the tire, and the position of the amount of unbalance on the periphery of the end surface of the wheel is measured; a predicted angle for assembling the tire and the wheel is obtained on the basis of the physical amount of unbalance using a predetermined evaluation function which includes a phase angle at the time of assembling the tire and the wheel for evaluating the relationship between the tire and the wheel at the time of assembly; and the tire and the wheel are assembled at the predicted angle.
In the first and second aspects of the present invention, on the basis of the physical amount of unbalance which includes the magnitude and the position of the amount of unbalance of the tire and the magnitude and the position of the amount of unbalance of the wheel for assembling with the tire, the predicted angle for assembling the tire and the wheel is obtained using the predetermined evaluation function for evaluating the relationship between the tire and the wheel at the time of assembly. The tire and the wheel are assembled at this predicted angle.
The magnitudes and the positions of the amounts of unbalance of the tire and the wheel, which comprises the physical amount of unbalance, can be obtained by measuring or can be obtained using values which have been already measured. This physical amount of unbalance includes, for example, the magnitude and the phase (position) of a static unbalance, and the evaluation function can use the static unbalance after the tire and the wheel are assembled. Normally, it is desirable that the static unbalance is made small. When the single tire unit and the single wheel unit are assembled so that each phase (position) of the static unbalance thereof is 180 degrees, it can be expected that the amount of static unbalance after the tire and the wheel are assembled will be reduced. Accordingly, the amount of unbalance to be corrected can be made as small as possible at the time of assembling the wheel and the tire, and the magnitude of the balance weight which should be the magnitude of the amount of unbalance to be corrected after the wheel and the tire are assembled can be reduced. Consequently, even if iron whose specific gravity is smaller than that of lead which has been conventionally used is used, the amount of unbalance itself can be reduced. Thus, correction of unbalance can be effected without increasing the volume of the iron used.
Therefore, in accordance with the third aspect of the present invention, when an evaluation function which indicates the magnitude of the amount of static unbalance correction after the tire and the wheel are assembled is used, and the tire and the wheel are assembled at the predicted angle of, for example, 180 degrees which can optimize the amount of unbalance to be corrected, the balance weight for correcting the unbalance can be made small.
The phase (position) can be set to 180 degrees, the value which is in the vicinity of 180 degrees, or a predetermined range. The evaluation function may be determined so that the amount of static unbalance after the assembling is a predetermined value.
The physical amount of unbalance can include the magnitude of the amount of unbalance on the axial direction end surfaces of the tire, the position of the amount of unbalance on the periphery of the end surface of the tire, the magnitude of amount of unbalance on the axial direction end surfaces of the wheel for assembling with the tire and the position of the amount of unbalance on the periphery of the end surface of the wheel.
On the basis of these physical amounts of unbalance, the predicted angle for assembling the tire and the wheel is obtained using the predetermined evaluation function which includes the phase angle at the time of assembling the tire and the wheel for evaluating the relationship between the tire and the wheel at the time of assembly. In this case, the deviated angle at the time in which the predetermined reference positions on the peripheries of the tire and the wheel are deviated from each other and assembled is the phase angle at the time of assembling the tire and the wheel, and the phase angle is used as a parameter. The relationship between the tire and the wheel at the time of assembly is evaluated and, for example, the magnitude or the like of the amount of unbalance to be corrected at the phase angle is obtained. The phase angle at the time of assembling the wheel and the tire which can optimize this evaluation function is predicted and the predicted phase angle is made the predicted angle. Then, the tire and the wheel are assembled by the obtained predicted angle.
In this way, since the tire and the wheel are assembled at the predicted angle which can optimize the evaluation function, the amount of unbalance to be corrected can be made as small as possible at the time of assembling the tire and the wheel, and the magnitude of a balance weight which should be the magnitude of the amount of unbalance to be corrected after the wheel and the tire are assembled can be reduced. Consequently, even if iron whose specific gravity is smaller than that of lead, which has been conventionally used, is used, the amount of unbalance to be corrected itself can be reduced. Thus, correction of unbalance can be effected without increasing the volume of the iron used.
Even when the amount of unbalance on the axial direction end surfaces of the tire and the amount of unbalance on the axial direction end surfaces of the wheel are used as the physical amount of unbalance, in accordance with the third aspect of the present invention, the evaluation function which indicates the magnitude of the amount of static unbalance to be corrected after the tire and the wheel are assembled can be used. In this way, when the tire and the wheel are assembled so that the phase formed by the amount of unbalance on the axial direction end surfaces of the wheel and the phase formed by the amount of unbalance on the axial direction end surfaces of the tire is, for example, 180 degrees which can optimize the amount of unbalance to be corrected, the balance weight for correcting the unbalance can be made small.
In accordance with the fourth aspect of the present invention, the evaluation function which indicates the magnitude of at least one of the amounts of unbalance to be corrected on the axial direction end surfaces of the wheel after the tire and the wheel are assembled can be used. The magnitude of the amount of unbalance to be corrected at the phase angle is obtained by this evaluation function. When the phase angle at the time of assembling the wheel and the tire which allows the amount of unbalance to be corrected to be optimized (e.g., which allows the magnitude of the balance weight to be reduced, which allows the magnitude of the balance weight to be set to a predetermined value, or which allows the magnitude of the balance weight to be set to a value within a predetermined range) is set as a predicted angle and the tire and the wheel are assembled at the predicted angle, the amount of unbalance to be corrected is reduced and the balance weight for correcting the unbalance can be made small.
In accordance with the fifth aspect of the present invention, the physical amount of unbalance can further include the physical amount relating to the radial direction vibrations of the tire and the physical amount relating to the radial direction vibrations of the wheel. In this case, the evaluation function which indicates the physical amounts relating to the radial direction vibrations of the tire and the wheel after the tire and the wheel are assembled can be used. As a result, the phase angle which can optimize the amount of unbalance to be corrected, e.g., which can reduce the RFV primary component or the like after the wheel and the tire are assembled, can be obtained as the predicted angle. When the tire and the wheel are assembled at the predicted angle, the amount of unbalance to be corrected, e.g., the magnitude of the balance weight or the RFV primary component, can be made as small as possible, can be set to a predetermined value, or can be set to a value within a predetermined range. Thus, it is easy to assemble the wheel and the tire.
In accordance with the sixth aspect of the present invention, an evaluation function can be used which indicates the sum of the physical amount of the magnitude of at least one of the amounts of unbalance correction on the axial direction end surfaces of the wheel after the wheel and the tire are assembled and a weight is attached thereto, and the physical amount relating to the radial direction vibrations of the wheel and the tire after the tire and the wheel are assembled and a weight is attached thereto. Since the physical amounts are weighted in this way, the relationship between the tire and the wheel at the time of assembly can be evaluated by the linear sum of the amounts of unbalance. As a result, the amount of unbalance to be corrected, e.g., the magnitude of the balance weight, the RFV primary component, or the like, can be made as small as possible, can be set to a predetermined value, or can be set to a value within the predetermined range. Thus, the optimum phase angle at the time of assembling the tire and the wheel can be obtained.
Further, in accordance with the seventh aspect of the present invention, the weighted physical amounts of the evaluation function may have a predetermined relationship. In this way, the relationship is not limited to the evaluation by a linear sum and may be evaluated, e.g., by a non-linear function or the like. Moreover, a table which includes predetermined corresponding relationships on the physical amounts may be referred to and the physical amounts summed or calculated by a predetermined function to obtain the predetermined relationship. As a result, it is more flexible to, for example, reduce greatly the amount of unbalance to be corrected, e.g., the magnitude of the unbalance weight or the RFV primary component.
The air intake valve is attached to the wheel, and the weight of this air intake valve may contribute to the unbalance. Thus, in accordance with the eighth aspect of the present invention, the wheel, to which the valve for intaking air is attached, is used. As a result, the optimum phase angle for assembling the tire and the wheel, to which the actual air intake valve is attached, can be obtained.
In accordance with the ninth aspect of the present invention, the physical amount relating to the radial direction vibrations of the wheel can use the radial run-out, and the physical amount relating to the radial direction vibrations of the tire can use at least one uniformity of the radial force variation and the lateral force variation.
The predicted angle which is an optimum phase angle for assembling the tire and the wheel is obtained by a record medium which stores a phase angle operating program having the following procedures. The storage medium which stores the program is easily portable allowing the program to be used on-site when the tires and wheels are being assembled.
Namely, the recording medium which records the phase angle operating program of the tenth aspect of the present invention is the record medium which records the phase angle operating program at the time of assembling the tire and the wheel in which the optimum phase angle at the time of assembling the tire and the wheel is obtained by the computer as the predicted angle, wherein: the physical amount of unbalance which includes the magnitude of an amount of unbalance on the axial direction end surfaces of the tire, the position of an amount of unbalance on the periphery of the end surface of the tire, the magnitude of an amount of unbalance on the axial direction end surfaces of the wheel for assembling with the tire, and the position of an amount of unbalance on the periphery of the end surface of the wheel is measured; and the predicted angle for assembling the tire and the wheel is obtained on the basis of the physical amount of unbalance using the predetermined evaluation function which includes the phase angle at the time of assembling the tire and the wheel for evaluating the relationship between the tire and the wheel.
In accordance with the method of assembling the tire and the wheel in which the predicted angle of the tire and the wheel is obtained and the tire and the wheel are assembled at the predicted angle, the following assembled tire and wheel unit can be obtained. Namely, in accordance with the eleventh aspect of the present invention, the assembled tire and wheel unit, wherein: the physical amount of unbalance which includes the magnitude of an amount of unbalance on the axial direction end surfaces of the tire, the position of an amount of unbalance on the periphery of the end surface of the tire, the magnitude of an amount of unbalance on the axial direction end surfaces of the wheel for assembling with the tire, and the position of an amount of unbalance on the periphery of the end surface of the wheel is measured; the predicted angle for assembling the tire and the wheel is obtained on the basis of the physical amount of unbalance using the predetermined evaluation function which includes the phase angle at the time of assembling the tire and the wheel for evaluating the relationship between the tire and the wheel; and the tire and the wheel are assembled at the predicted angle.